User interface on a display device



FIG. 1 is a front view of the user interface on a display screen; and,

FIG. 2 is a front view of thereof, but shown without text in broken lines.

The broken line showing of the text, broken line regions and screen is included for the purpose of illustrating an active menu and a display device and forms no part of the claimed design. 

The ornamental design for a user interface on a display device, as shown and described. 